The act of discrediting a political opponent by making exaggurated or outrightly false claims about his/her character and past actions.
Coined from the 2004 US Presidential campaign, where the the conservative group Swift Boat Veterans for Truth aired a commercial criticizing democrat John Kerry's reputation as a war hero in Vietnam. It has since become a popular term with leftist journalists.
Jed: Sylva says she's against the war, but she has no idea about how much it protects our country. It's not like she actually earned her PhD in political science - her daddy has influence at that college.
Alex: Dude, stop swift boating my girlfriend!